A remote monitoring device that is specific to the fall prevention and protection has been developed by the present inventor Baillargeon and is described in pending U.S. Patent Publication No. 20120217091. The invention discloses a monitoring system that delivers warning messages and critical information to aerial lift operators to remind and enforce safety regulations including the attachment of a safety lanyard prior to movement of a work platform or bucket of an aerial lift. Construction and aerial lift machinery apparatus present significant risks and danger not only to the operators, but to those in proximity to the machinery. To address these issues, safety devices such as lanyards or safety harness detection sensors, motion and high voltage proximity sensors and other warning devices to protect the operator have been developed.
Additional patents to Baillargeon and others include U.S. Pat. No. 6,330,931 that describes a safety lanyard detection sensor and warning device which inhibits operation of the machinery and also can deliver a visual or audible message to the operator that machinery movement is inhibited because of failure by the operator to secure a safety lanyard. Also, U.S. Pat. No. 6,297,744 discloses a warning device that delivers messages to the operator to secure their safety lanyard at an initial upward movement of the work platform and delivers messages within the area below the boom and work platform or zone of danger that the boom is moving, expressing that persons below the boom should remain out of the area as the boom descends.
In both of the Baillargeon U.S. Pat. Nos. 6,330,931 and 6,265,983, the lanyard detection sensor disclosed is located on the lift anchor point. Upward movement of the work platform is inhibited via an interlock switch unless the lanyard detection sensor detects that the lift operator has attached a safety lanyard to the lift anchor point. An issue in this approach is that the system may be defeated by leaving the safety lanyard attached to the anchor point at all times. An operator may forget or otherwise fail to secure the lanyard to themselves, and can even leave the work platform and in such a situation leave the lanyard on the anchor point allowing operation of the platform without a secure attachment of the lanyard to the body harness of the operator creating a hazardous risk to the operator. In these real life scenarios, the unprotected lift operators will be able to go up in the work platform without proper utilization of their fall protection apparatus because the sensor has detected the attachment of the lanyard to the anchor point enabling lift movement without the safety lanyard being attached to the harness worn by the lift operator.
The interface monitoring device described in pending U.S. Patent Publication No. 2012/0217091 to Baillargeon includes data logging features that track telematics data specific to the operator and aerial lift device including the time and operational steps taken after connecting the safety lanyard. This information is stored and transmitted to supervisors and others to monitor and track fault conditions and safety violations in the operation of an aerial lift device. The system further provides data and warnings on severe fault conditions, such as an overload in the bucket or an outrigger stability warning and a transmission to emergency personal that an operator may be in distress. What is not disclosed in this prior art, is a load sensor affixed to the fall arresting/prevention device that when activated transmits an emergency warning signal to emergency personal, supervisors and others that a severe fault condition involving the operator falling out of and being suspended from the bucket of the aerial lift device.
A serious complication for an operator suspended vertically within a harness is suspension trauma which may result in death for the operator. This harness-induced death may occur in a wide range of situations and in safety harnesses of various types. Operators requiring fall protection, use safety harnesses, belts, and seats that suspend the operator in a vertical upright position that if held for a period of time of roughly about five minutes can cause the legs to relax straight beneath the body which results in suspension trauma caused by orthostatic incompetence (also called orthostatic intolerance). In orthostatic incompetence the legs are immobile with the operator in an upright posture. Gravity pulls blood into the lower legs, which have a very large storage capacity and as enough blood accumulates the return blood flow to the right chamber of the heart is reduced. The heart can only pump available blood and therefore the heart's output begins to fall. The heart speeds up to maintain sufficient blood flow to the brain, but if the blood supply to the heart is restricted enough, beating faster is ineffective, and the body abruptly slows the heart. In most instances this solves the problem by causing the operator to faint, which typically results in slumping to the ground where the legs, the heart, and the brain are on the same level. Blood is now returned to the heart and the operator typically recovers quickly. In a harness, however, the operator can't fall into a horizontal posture, so the reduced heart rate causes the brain's blood supply to fall below the critical level.
For an operator that falls from a bucket or work platform and is suspended in an upright posture with legs dangling, the safety harness straps exert pressure on leg veins, compressing them and reducing blood flow back to the heart. The operator in only a short period of time may lose consciousness, which is what kills the operator with emergency personal arriving too late to revive the operator. While a fall victim can slow the onset of suspension trauma by pushing down vigorously with the legs, and attempting to position their body in a horizontal or slight leg-high position, most harness designs do not provide proper support or attachments for the operator to maneuver their body into a horizontal position and if the operator is injured, pulling their own weight to align their body horizontally may be difficult. Rescue must come rapidly to minimize the dangers of suspension trauma or preferably with the minimal amount of time available the operator must be able to take the proper steps to save themselves. The present invention has a number of features to address this issue and the safety of the operator including a remote control of the work platform or aerial lift bucket that provides for an operator to raise themselves back to the work platform or bucket, or lower themselves to the ground after a fall.